/*******************************************************************************
 * Copyright (c) 2000, 2007 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Tom Schindl <tom.schindl@bestsolution.at> - bugfix in 199775
 *******************************************************************************/

package fr.emse.tatiana.utils;

import java.text.MessageFormat;	// Not using ICU to support standalone JFace scenario

import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.viewers.CellEditor;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.CCombo;
import org.eclipse.swt.events.FocusAdapter;
import org.eclipse.swt.events.FocusEvent;
import org.eclipse.swt.events.KeyAdapter;
import org.eclipse.swt.events.KeyEvent;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.TraverseEvent;
import org.eclipse.swt.events.TraverseListener;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;

/**
 * A cell editor that presents a list of items in a combo box.
 * The cell editor's value is the zero-based index of the selected
 * item.
 * <p>
 * This class may be instantiated; it is not intended to be subclassed.
 * </p>
 */
public class AutocompleteComboBoxCellEditor extends CellEditor {

    /**
     * The list of items to present in the combo box.
     */
    private String[] items;

    /**
     * The zero-based index of the selected item.
     */
    int selection;

    /**
     * The custom combo box control.
     */
    CCombo comboBox;

    /**
     * Default ComboBoxCellEditor style
     */
    private static final int defaultStyle = SWT.NONE;

    /**
     * Creates a new cell editor with no control and no  st of choices. Initially,
     * the cell editor has no cell validator.
     * 
     * @since 2.1
     * @see CellEditor#setStyle
     * @see CellEditor#create
     * @see AutocompleteComboBoxCellEditor#setItems
     * @see CellEditor#dispose
     */
    public AutocompleteComboBoxCellEditor() {
        setStyle(defaultStyle);
    }

    /**
     * Creates a new cell editor with a combo containing the given 
     * list of choices and parented under the given control. The cell
     * editor value is the zero-based index of the selected item.
     * Initially, the cell editor has no cell validator and
     * the first item in the list is selected. 
     *
     * @param parent the parent control
     * @param items the list of strings for the combo box
     */
    public AutocompleteComboBoxCellEditor(Composite parent, String[] items) {
        this(parent, items, defaultStyle);
    }

    /**
     * Creates a new cell editor with a combo containing the given 
     * list of choices and parented under the given control. The cell
     * editor value is the zero-based index of the selected item.
     * Initially, the cell editor has no cell validator and
     * the first item in the list is selected. 
     *
     * @param parent the parent control
     * @param items the list of strings for the combo box
     * @param style the style bits
     * @since 2.1
     */
    public AutocompleteComboBoxCellEditor(Composite parent, String[] items, int style) {
        super(parent, style);
        setItems(items);
    }

    /**
     * Returns the list of choices for the combo box
     *
     * @return the list of choices for the combo box
     */
    public String[] getItems() {
        return this.items;
    }

    /**
     * Sets the list of choices for the combo box
     *
     * @param items the list of choices for the combo box
     */
    public void setItems(String[] items) {
        Assert.isNotNull(items);
        this.items = items;
        populateComboBoxItems();
    }

    /* (non-Javadoc)
     * Method declared on CellEditor.
     */
    @Override
	protected Control createControl(Composite parent) {

        comboBox = new CCombo(parent, getStyle());
        comboBox.setFont(parent.getFont());
        
        populateComboBoxItems();

        comboBox.addKeyListener(new KeyAdapter() {
            // hook key pressed - see PR 14201  
            @Override
			public void keyPressed(KeyEvent e) {
                keyReleaseOccured(e);
            }
        });

        comboBox.addSelectionListener(new SelectionAdapter() {
            @Override
			public void widgetDefaultSelected(SelectionEvent event) {
                applyEditorValueAndDeactivate();
            }

            @Override
			public void widgetSelected(SelectionEvent event) {
                selection = comboBox.getSelectionIndex();
            }
        });

        comboBox.addTraverseListener(new TraverseListener() {
            public void keyTraversed(TraverseEvent e) {
                if (e.detail == SWT.TRAVERSE_ESCAPE
                        || e.detail == SWT.TRAVERSE_RETURN) {
                    e.doit = false;
                }
            }
        });

        comboBox.addFocusListener(new FocusAdapter() {
            @Override
			public void focusLost(FocusEvent e) {
                AutocompleteComboBoxCellEditor.this.focusLost();
            }
        });
        return comboBox;
    }

    /**
     * The <code>ComboBoxCellEditor</code> implementation of
     * this <code>CellEditor</code> framework method returns
     * the zero-based index of the current selection.
     *
     * @return the zero-based index of the current selection wrapped
     *  as an <code>Integer</code>
     */
    @Override
	protected Object doGetValue() {
        return new Integer(selection);
    }

    /* (non-Javadoc)
     * Method declared on CellEditor.
     */
    @Override
	protected void doSetFocus() {
        comboBox.setFocus();
    }

    /**
     * The <code>ComboBoxCellEditor</code> implementation of
     * this <code>CellEditor</code> framework method sets the 
     * minimum width of the cell.  The minimum width is 10 characters
     * if <code>comboBox</code> is not <code>null</code> or <code>disposed</code>
     * else it is 60 pixels to make sure the arrow button and some text is visible.
     * The list of CCombo will be wide enough to show its longest item.
     */
    @Override
	public LayoutData getLayoutData() {
        LayoutData layoutData = super.getLayoutData();
        if ((comboBox == null) || comboBox.isDisposed()) {
			layoutData.minimumWidth = 60;
		} else {
            // make the comboBox 10 characters wide
            GC gc = new GC(comboBox);
            layoutData.minimumWidth = (gc.getFontMetrics()
                    .getAverageCharWidth() * 10) + 10;
            gc.dispose();
        }
        return layoutData;
    }

    /**
     * The <code>ComboBoxCellEditor</code> implementation of
     * this <code>CellEditor</code> framework method
     * accepts a zero-based index of a selection.
     *
     * @param value the zero-based index of the selection wrapped
     *   as an <code>Integer</code>
     */
    @Override
	protected void doSetValue(Object value) {
        Assert.isTrue(comboBox != null && (value instanceof Integer));
        selection = ((Integer) value).intValue();
        comboBox.select(selection);
    }

    /**
     * Updates the list of choices for the combo box for the current control.
     */
    private void populateComboBoxItems() {
        if (comboBox != null && items != null) {
            comboBox.removeAll();
            for (int i = 0; i < items.length; i++) {
				comboBox.add(items[i], i);
			}

            setValueValid(true);
            selection = 0;
        }
    }

    /**
     * Applies the currently selected value and deactivates the cell editor
     */
    void applyEditorValueAndDeactivate() {
        //	must set the selection before getting value
        selection = comboBox.getSelectionIndex();
        Object newValue = doGetValue();
        markDirty();
        boolean isValid = isCorrect(newValue);
        setValueValid(isValid);
        
        if (!isValid) {
        	// Only format if the 'index' is valid
        	if (items.length > 0 && selection >= 0 && selection < items.length) {
	            // try to insert the current value into the error message.
	            setErrorMessage(MessageFormat.format(getErrorMessage(),
	                    new Object[] { items[selection] }));
        	}
        	else {
	            // Since we don't have a valid index, assume we're using an 'edit'
        		// combo so format using its text value
	            setErrorMessage(MessageFormat.format(getErrorMessage(),
	                    new Object[] { comboBox.getText() }));
        	}
        }

        fireApplyEditorValue();
        deactivate();
    }

    /*
     *  (non-Javadoc)
     * @see org.eclipse.jface.viewers.CellEditor#focusLost()
     */
    @Override
	protected void focusLost() {
        if (isActivated()) {
            applyEditorValueAndDeactivate();
        }
    }

	private int lastEnteredTime = -1;
    private String enteredString = "";
    
    
    /*
     *  (non-Javadoc)
     * @see org.eclipse.jface.viewers.CellEditor#keyReleaseOccured(org.eclipse.swt.events.KeyEvent)
     */
    @Override
	protected void keyReleaseOccured(KeyEvent keyEvent) {
        if (keyEvent.character == '\u001b') { // Escape character
            fireCancelEditor();
        } else if (keyEvent.character == '\t') { // tab key
            applyEditorValueAndDeactivate();
        } else if (keyEvent.keyCode == SWT.ARROW_UP || keyEvent.keyCode == SWT.ARROW_DOWN 
        		|| keyEvent.character == '\t' || keyEvent.character=='\u001b') {
        	return; 
        	
        } else {
        	if (lastEnteredTime == -1)
        		lastEnteredTime = keyEvent.time;
        	else if (keyEvent.time - lastEnteredTime > 1000) {
        		// A longer than ~1 second delay, resets the entryString.
        		lastEnteredTime = keyEvent.time;
        		enteredString = ""; //$NON-NLS-1$
        	}
        	final String potentialEnteredString = (enteredString + 
        			String.valueOf(keyEvent.character)).toUpperCase();
        	final String[] tempItems = this.getItems();
        	for (int i = 0; i < tempItems.length; i++) {
        		final String aString = tempItems[i];
        		if (aString.equalsIgnoreCase(potentialEnteredString)) {
	    			   enteredString = ""; //$NON-NLS-1$
	    			   this.doSetValue(new Integer(i));
	    			   break;
	    		   } else if 
	    		   (aString.toUpperCase().startsWith(potentialEnteredString)) {
	    			   enteredString = potentialEnteredString;
	    			   this.doSetValue(new Integer(i));
	    			   break;
	    		   };
//	    		   e.doit = false;
	    	   }
	       }
    }

	@Override
	public void deactivate() {
		super.deactivate();
		comboBox.getParent().forceFocus();
	}
}
